DEVELOPMENT OF LOW FREQUENCY MEG HARDWARE AND SOFTWARE

我们正在进行的研究目标是开发硬件、软件和技术，以扩大脑磁图（MEG）的应用，作为临床诊断工具和神经科学基础研究的一种模式。在我们的实验室里，有了一个大阵列的全头部神经磁强计，这样的系统变得越来越普遍，但价格相当高，MEG的额外效用的演示变得更加重要。该实验室开发的复杂数学分析技术、有限差分场映射（FDFM）和二维逆成像（2DII）以及几个商业软件包将应用于从潜在癫痫手术患者收集的临床数据，用于术前映射和源定位。这些技术的结果将与在许多机构进行的标准等效电流偶极子（ECD）分析进行系统比较。利用颞叶癫痫患者脑电后产生的伪直流磁场进行源定位的第二种方法也将使用癫痫手术候选人进行研究。直流脑磁图技术将用于偏头痛和中风患者的持续研究。在下一个拨款期内，将使用MEG信号研究有先兆偏头痛和无先兆偏头痛（经典偏头痛和普通偏头痛）之间的生理差异和相似之处，这些信号与动物模型中扩散性皮质抑制测量的信号基本相同。将开发使用脑磁图测量来确定脑卒中患者康复和恢复的方法。在上述所有研究中，将使用相同条件下完善的动物模型中产生的MEG信号来验证在人类中检测到的MEG信号的性质。这些研究将在三种动物身上进行，它们的大脑皮层越来越复杂，分别是大鼠、兔子和猪。使用动态周期分析（DPA）来产生伴随觉醒变化和睡眠的皮质活动变化的整个头部映射将被研究。2DII成像将用于定义与睡眠相关的主动离散和扩展源活动。脑磁图的空间和时间分辨率将用于研究失读症受试者，并定位异常活动区域。将使用一系列视觉/听觉刺激，包括文字、图片和形状识别。如果在青少年阅读障碍患者身上取得成功，这项研究将扩展到儿童和其他有学习障碍的人身上。

The ongoing objective of our research has been to develop hardware, software, and techniques to expand the utility of Magnetoencephalography (MEG), both as a clinical diagnostic tool, and as a modality for basic studies in the neurosciences. With a large array, whole head neuromagnetometer now available in our lab, and such systems becoming more generally available, but at quite high prices, the demonstration of added utility for MEG becomes even more significant. Sophisticated mathematical analytical techniques develooped in this lab, finite difference field mapping (FDFM) and two dimensional inverse imaging (2DII), as well as several commercial software packages, will be applied to clinical data gathered from potential epilepsy surgery patients, for presurgical mapping and source localization. The results of these techniques will be systematically compared to the standard equivalent current dipole (ECD) analysis, carried out at a number of institutions. A second method of source location utilizing the pseudo-DC magnetic fields arising post- ictally in temporal lobe epilepsy patients will also be studied using epilepsy surgery candidates. DC MEG techniques will be utilized for a continuing study of migraine and stroke patients. During the next grant period the physiological differences and similarities between migraine with aura and migraine without aura (classic and common migraine) will be studied using MEG signals essentially identical to signals measured from spreading cortical depression in animal models. Methods for using MEG measurements for determining rehabilitation and recovery in stroke patients will be developed. In all of the foregoing studies, the nature of the MEG signals detected in humans will be validated using the MEG signals arising from well-established animal models of the same conditions. These studies will be conducted in three species with progressively more complex cortexes, rat, rabbit, and swine. The use of dynamic period analysis (DPA) to produce whole head mapping of the changes in cortical activity accompanying arousal changes and sleep will be studied. 2DII imaging will be used to define active discrete and extended source activity associated with sleep. The spatial and temporal resolution of MEG will be utilized to study dyslexic subjects, and to localize regions of abnormal activity. A series of visual/auditory stimuli involving word, picture, and shape recognition will be used. If successful with young adult dyslexics, the study will be extended the study to children and individuals with other learning disabilities.